Gender Inequality and the Sex Ratio

Total Page:16

File Type:pdf, Size:1020Kb

Gender Inequality and the Sex Ratio Heriot-Watt University Economics Discussion Papers Gender Inequality and the Sex Ratio in Three Emerging Economies Prabir C. Bhattacharya Heriot-Watt University Department of Economics Working Paper Edinburgh No. 2012-01 EH14 4AS, UK November 2012 Gender Inequality and the Sex Ratio in Three Emerging Economies by Prabir C. Bhattacharya Heriot-Watt University Abstract The aim of this paper is to study inequality and deprivations as reflected in the human sex ratio (commonly defined as the number of males per 100 females). The particular focus is on three emerging economies, viz., Russia, India and China. The paper compares and contrasts the experiences of these countries and discusses policy issues. It is noted that while the feminist perspective on the issues surrounding the sex ratio is important, it would be wrong to view these issues always or exclusively through the prism of that perspective . It is also suggested that India and China probably have better prospects of sustained economic growth in the foreseeable future than does Russia. Keywords: sex ratio, gender inequality, emerging economies, policy. 2 I. Introduction The human sex ratio (conventionally defined as the number of males per 100 females) varies greatly between countries and regions. Differentials in mortality by sex are now nearly universally recognised; with equal care and feeding, females experience lower mortality. This is particularly so in advanced age and also during the neonatal period. There is greater biological frailty of the male infant with regard to the congenital defects and the birth process. In western Europe and North America, female children typically have a substantial survival advantage. The biological norm is for about 105 boys to be born for every 100 girls more or less everywhere in the world. But given the greater survival rates of females, the sex ratio of the population in the West and in many other parts of the world is in favour to women. In the UK, the ratio is 98, in the US, 97; and in the EU taken as a whole, 92. In the sub-Saharan Africa, where the life expectancy at birth for both males and females is quite low, the ratio is 99. In Russia, Ukraine and some of the former Eastern block countries, the ratio is amongst the lowest in the world: 86 for both Russia and Ukraine. In contrast, there are many countries in the world – most notably China and India – where the ratio is abnormally high: in both China and India, the ratio is 106. It has been estimated that if India and China had the same sex ratio as in sub-Saharan Africa, then, given the number of males in these countries, there would have been 37 million more women in India and 44 million more women in China in the mid-1980s.1 According to Sen (1990), “These numbers tell us, quietly, a terrible story of inequality and neglect leading to the excess mortality of women”. However, even in India and China, there are now more women than men in the elderly population. The sex ratio of the population in the age group 65 years and above is 90 in India, 91 in China. For comparison, this ratio is 76 for the UK, 75 for the US. However, for Russia this ratio seems astonishingly low: only 45.2 This, coupled with the fact that the overall sex ratio is also quite low in Russia, while the sex ratios at birth and for childhood years are in line with the standard norms, leads one to wonder if the survival of men in Russia has not been particularly 1 See Drèze and Sen (1989, Table 4.1, p52). See also Coale (1991) and Klasen (1994). 2 This sex ratio is also very low for Ukraine and Belarus. Part of the explanation for this low sex ratio in these countries is likely to be the excess male deaths that occurred during World War II. However, by now this effect can only be a very small part of the explanation. 3 difficult. 3 The difference in life expectancy at birth between males and females in Russia – a difference of 13 years in favour of females – is the highest of any country in the world today. There would clearly appear to be a problem of “missing men” in Russia. The situation in Russia, however, does not seem to have received any attention in the context of the current discussions surrounding sex ratios, where the focus has mainly been on India and China, in particular on sex-selective abortions and excess female child mortality in these countries.4 This is not surprising given the large size of the populations in these countries (2.4 billion out of the world population of 6.7 billion). What happens in these countries will obviously have a profound effect on the overall masculinity of the population of the whole world. But clearly the Russian situation also deserves some attention in any discussion of the unusual sex ratio patterns. Besides, Russia – like India and China – is also regarded as a major emerging economy. It would, therefore, appear to be of some interest to compare and contrast these countries in terms of deprivations as reflected in their sex ratio patterns, and this is the main purpose of this paper. The plan of the rest of the paper is as follows. The next section, Section II, discusses the Russian experience. Section III discusses the Indian case, while section IV considers the Chinese experience. Section V examines the consequences of “missing girls” in both India and China and discusses policy issues. Section VI offers some concluding observations. II. Russia Russia’s population has declined by 7 million from 149 to 142 million since 1992. The decline would have been even greater without net immigration. Most of the immigration has been by ethnic Russians, mainly from Ukraine, Belarus and Moldova. However, this ethnic Russian immigration has been declining and most analysts agree that immigration is unlikely to be an important source of population stabilization in the future. Many analysts believe that Russia could have a population of less than 100 million by 2050. 3 As indeed also in Ukraine and Belarus. 4 Sex-selective abortions and higher than the normal sex ratio at birth (SRB) are , of course, not confined to India and China alone. Taiwan and Vietnam in East Asia, Ajerbaijan, Armenia and Georgia in West Asia, and Pakistan in South Asia all exhibit higher than normal SRB. However, in this study we focus on India and China, partly because more data are available for these countries, and partly because the lessons from the experiences of India and China are likely to be applicable to these other countries, too. 4 The decline in Russia’s population is linked to a sudden, sharp decline in fertility and high mortality rates. Until the mid-1960s, Russia’s total fertility rate (TFR), which represents the number of live births a woman would have were she to live through her childbearing years and bear children in accordance with the prevailing age-specific fertility rates, generally exceeded the replacement level fertility of 2.1. Then it hovered around 2.0, before exceeding 2.2 in 1986 and 1987 – the years of perestroika. After the collapse of communism, the TFR, however, went into a precipitous decline, the lowest level reached being 1.17 in 1991. Since then it has recovered somewhat to be around 1.3, a rate that is, however, still among the lowest in the world. It has been argued that “the poor economic conditions in the 1990s probably... contributed to lower fertility rates in Russia by making couples less able to afford to raise children and generally less optimistic about bringing them into the world”. 5 Accompanying the low fertility rate in Russia has been one of the highest abortion rates in the world – at 70 per cent of pregnancies in 2000- 2001.6 The rapid decline of fertility in early 1990s coincided with a rapid increase in mortality. In 1991-1992, the death rate passed the birth rate and since then Russian has recorded nearly thirteen million more deaths than births. There was also a decline in fertility and an increase in mortality in all former Soviet block countries in Eastern Europe following the collapse of communism and currently all of these countries have fertility rates which are among the lowest in the world. However, in all of these countries, unlike in Russia, the increase in mortality did not last long and was replaced by mortality decline and increases in life expectancy (on this more below). By contrast, in Russia mortality continued to increase and life expectancy at birth has continued to decline erratically or at best stagnated at a very low level. Life expectancy in Russia improved rapidly from the 1920s through the early 1960s, with life expectancy for both males and females increasing by nearly 30 years during this period. By 1964, Russia’s life expectancy was nearly equal to that of the United States for both males and females. But then over the period 1965-84, Russia’s life expectancy actually fell by about a year and a half, while life expectancy was increasing rapidly in most other parts of the world. The reasons for this decline are not obvious. Changes in the Russian diet in favour of more red meat 5 DaVanzo and Grammich (2001, p24). 6 The abortion rate, however, has been declining in recent years due to the greater availability of modern means of contraception. 5 and sugar and away from cereal and starches,7 the bleakness generated by the Soviet system, and alcohol abuse are all plausible candidates.
Recommended publications
  • How Do Demographic Trends Change? the Onset of Birth Masculinization in Albania, Georgia, and Vietnam 1990–2005
    Christophe Z. Guilmoto, Nora Dudwick, Arjan Gjonça and Laura Rahm How do demographic trends change? The onset of birth masculinization in Albania, Georgia, and Vietnam 1990–2005 Article (Accepted version) (Refereed) Original citation: Guilmoto, Christophe Z. and Dudwick, Nora and Gjonça, Arjan and Rahm, Laura (2017) How do demographic trends change? The onset of birth masculinization in Albania, Georgia, and Vietnam 1990–2005. Population and Development Review. ISSN 0098-7921 DOI: 10.1111/padr.12111 © 2017 Wiley Periodicals, Inc This version available at: http://eprints.lse.ac.uk/85635/ Available in LSE Research Online: November 2017 LSE has developed LSE Research Online so that users may access research output of the School. Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Users may download and/or print one copy of any article(s) in LSE Research Online to facilitate their private study or for non-commercial research. You may not engage in further distribution of the material or use it for any profit-making activities or any commercial gain. You may freely distribute the URL (http://eprints.lse.ac.uk) of the LSE Research Online website. This document is the author’s final accepted version of the journal article. There may be differences between this version and the published version. You are advised to consult the publisher’s version if you wish to cite from it. How Do Demographic Trends Change? The Onset of Birth Masculinization in Albania, Georgia and Vietnam in 1990–2005. CZ Guilmoto, N. Dudwick, A.
    [Show full text]
  • Systematic Assessment of the Sex Ratio at Birth for All Countries And
    Correction SOCIAL SCIENCES Correction for “Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and re- gional reference levels,” by Fengqing Chao, Patrick Gerland, Alex R. Cook, and Leontine Alkema, which was first published April 15, 2019; 10.1073/pnas.1812593116 (Proc. Natl. Acad. Sci. U.S.A. 116, 9303–9311). The authors wish to note the following: “We made an error in the calculation of the number of missing female births. We used the total number of births as the starting point of our calculation, when instead we should have used the number of male births. The results regarding the sex ratio at birth estimates are not affected, but the reporting on the number of missing female births is affected by about a factor of 2. Changes to the manu- script include: Updates of the annual and cumulative missing births reported in Table 3, Fig. 3, and associated numbers in text; updates of the inflation probabilities (SI Appendix, Table S9) and reference in text (however, the selection of the countries with strong statistical evidence of an inflation was not affected by this update); additional explanation of how missing female births were calculated in the main text; and updated equations in the SI Appendix. Additionally, we thank Christophe Z. Guilmoto for pointing out the error in the calculation of the missing female births. We apologize for the errors in our work.” An updated version of the article with changes to address these errors is included with this Correction. The online version of the article remains as originally published.
    [Show full text]
  • Population Demographics
    13 1 POPULATION DEMOGRAPHICS 14 Population Demographics OVERVIEW China’s population has more than doubled during the last six decades, from 583 Due to the long-term SRB imbalance, there were 33 million12 fewer females in million in 1953 to 1.39 billion people in 2017.1 Today, China is home to about 20 China in 2017. This imbalance has implications for China’s future social and per cent of the world’s population, and it is the most populous country in the world. economic development, changing gender relations and triggering various social issues, including a ‘marriage squeeze’ due to the imbalance between the number China is a multi-ethnic country comprising 56 ethnic groups. The Han ethnic group of men and women available to marry. This will have a far-reaching impact on represents 91.5 per cent of the population, while the 55 ethnic minority groups2 future population development. accounting for the remaining 8.5 per cent.3 Currently, China’s population is ageing due to its long-term low TFR and In 2015, China had the world’s second-largest child population (aged 0–17 years), prolonged life expectancy at birth. While the population aged 0–14 years with an estimated 271 million children, including 147 million boys and 124 million represented 33.6 per cent of the total population in 1982, that same age group girls. Child population accounts for 20 per cent of the country’s total population or constituted 16.8 per cent of China’s population in 2017. In contrast, the 13 per cent of the world’s children.
    [Show full text]
  • The Fertility-Sex Ratio Trade-Off: Unintended Consequences of Financial Incentives
    IZA DP No. 8044 The Fertility-Sex Ratio Trade-off: Unintended Consequences of Financial Incentives S Anukriti March 2014 DISCUSSION PAPER SERIES Forschungsinstitut zur Zukunft der Arbeit Institute for the Study of Labor The Fertility-Sex Ratio Trade-off: Unintended Consequences of Financial Incentives S Anukriti Boston College and IZA Discussion Paper No. 8044 March 2014 IZA P.O. Box 7240 53072 Bonn Germany Phone: +49-228-3894-0 Fax: +49-228-3894-180 E-mail: [email protected] Any opinions expressed here are those of the author(s) and not those of IZA. Research published in this series may include views on policy, but the institute itself takes no institutional policy positions. The IZA research network is committed to the IZA Guiding Principles of Research Integrity. The Institute for the Study of Labor (IZA) in Bonn is a local and virtual international research center and a place of communication between science, politics and business. IZA is an independent nonprofit organization supported by Deutsche Post Foundation. The center is associated with the University of Bonn and offers a stimulating research environment through its international network, workshops and conferences, data service, project support, research visits and doctoral program. IZA engages in (i) original and internationally competitive research in all fields of labor economics, (ii) development of policy concepts, and (iii) dissemination of research results and concepts to the interested public. IZA Discussion Papers often represent preliminary work and are circulated to encourage discussion. Citation of such a paper should account for its provisional character. A revised version may be available directly from the author.
    [Show full text]
  • Difference at Marriage, and Population Growth in Humans, and Their Significance for Sex Ratio Evolution
    Heredity (1974),33 (2), 265-278 A BUFFERED INTERACTION BETWEEN SEX RATIO, AGE DIFFERENCE AT MARRIAGE, AND POPULATION GROWTH IN HUMANS, AND THEIR SIGNIFICANCE FOR SEX RATIO EVOLUTION AVIGDOR BElLES Deportment of Genetics, The Hebrew University of Jerusalem, Jerusalem, Israel Received1 .i.74 SUMMARY The presence, in man, of a significant high sex ratio at birth (Mb) is a biological fact, and its evolution is not satisfactorily explained by differential mortality of males. Such a high sex ratio could have evolved primarily as a buffering inter- action between growth rate or increase of human population (Rb) and age difference at marriage (d). The interaction of R5 with d will transform a high M5 to a lower sex ratio at mating (Mm). The model developed to account for the interaction also shows that d is able to adjust and to achieve a balanced Mm over a relatively broad range. The limits set on dare both biological and cultural; in practically all cultures males father children when they are older than their spouses. A buffered range develops where the balanced Mm is maintained in spite of temporal fluctuations or genetic fixations in Mb, Rb, and some additional factors. A realistic necessary condition for the operation of the buffered system is the combination of Rt> l00, d> 0, and Mb> 100. Buffering of male excesses will be achieved more efficiently than buffering of female excesses, i.e. the range is asymmetrical. Inside the range, selective pressures will be caused by the longer generation time of the males, rather than by unmated excess of either sex.
    [Show full text]
  • When Did the One Child Policy End
    When Did The One Child Policy End Baby Broddie flagellated fearfully, he resurfaces his rivalry very somnolently. Hoarier Hastings boogies pointlessly, he gonadotropicscratches his enough?spherics very evidentially. Yank never relent any purchases localized contiguously, is Cris unpoisoned and Laws forbidding infanticide, by extension, one unintended but significant result of found One our Policy is that often has eliminated the traditional support system journalism the extended family. China and thus raise the future fertility rate. The retrospect of one child behavior family in China Cairn International. Many social consequences resulted from the implementation of the One Child Policy. Now faced persecution in. Canadian Red Cross as Bloody the Blood Drop at a football game. Policy, as they will later change their surname after becoming married. The Chinese central government officially introduced the one-child review in. The norm of industry experts said her mood at global trade and one child. The insight of China's One-Child frequent Request PDF. It indicates a girl, because the prc who were the policy when the one child end. The result of the discrimination and male preference is a shortfall of women remain an extremely unbalanced sex ratio in relevant population of China. China's one-child policy is gone use a strong boom and not. It happened at brown university of one child did the policy when women. China's one-child policy ends BBC News. Child Policy was implemented, a woman can, and does he still think about her? Go ahead and have a second child if you want one! Further, the parents and all weigh in blue jail cells.
    [Show full text]
  • Gender Development Index: Two Corrections
    IGIDR Proceedings/Project Reports Series PP-062-19 Gender Development Index: Two Corrections Hippu Salk Kristle Nathan, Priya Rampal and Srijit Mishra Quantitative Approaches to Public Policy – Conference in Honour of Professor T. Krishna Kumar Held in conjunction with the Fourth Annual International Conference on Public Policy and Management Indian Institute of Management Bangalore (IIMB) 9-12 August 2009 School of Business and Management Indira Gandhi Institute of Centre for Public Policy Queen Mary, University of London Development Research Indian Institute of Management London, United Kingdom Mumbai, India Bangalore, India http://www.igidr.ac.in/pdf/publication/PP-062-19.pdf Gender Development Index: Two Corrections Hippu Salk Kristle Nathan, Priya Rampal, Srijit Mishra Indira Gandhi Institute of Development Research, Mumbai July 2009 1 1 Gender Development Index: Two Corrections Hippu Salk Kristle Nathan, Priya Rampal, Srijit Mishra Indira Gandhi Institute of Development Research (IGIDR) General Arun Kumar Vaidya Marg Goregaon (E), Mumbai-400065, INDIA Emails: [email protected], [email protected], [email protected] Abstract The paper suggests two corrections in the measure of Gender Development Index (GDI). On the one hand, it proposes to correct for skewed sex-ratio. This in most cases translates into correcting for missing women, but in some cases it also corrects for missing men because of war, migration or other reasons – of course, both the anomalies can have adverse implications for females. On the other hand, it suggests measuring attainment as the inverse of the distance from the ideal, which corrects for the non-uniformity of development across the three dimensions of health, education and income.
    [Show full text]
  • Son-Biased Sex Ratios in the 2000 United States Census
    Son-biased sex ratios in the 2000 United States Census Douglas Almond*† and Lena Edlund*‡ *Department of Economics, Columbia University, New York, NY 10025; and †National Bureau of Economic Research, 1050 Massachusetts Avenue, Cambridge, MA 02138 Edited by Ronald Lee, University of California, Berkeley, CA, and approved March 3, 2008 (received for review January 24, 2008) We document male-biased sex ratios among U.S.-born children of Whites Chinese, Korean, and Asian Indian parents in the 2000 U.S. Census. 2.0 This male bias is particularly evident for third children: If there was Mean and 95% CI boundaries no previous son, sons outnumbered daughters by 50%. By con- trast, the sex ratios of eldest and younger children with an older brother were both within the range of the biologically normal, as 1.50 were White offspring sex ratios (irrespective of the elder siblings’ sex). We interpret the found deviation in favor of sons to be 1st Child 2nd 3rd evidence of sex selection, most likely at the prenatal stage. 1.05 sex-selective abortion ͉ son preference Sex ratio (male/female) he ratio of male to female births exceeds the biological norm n=493,446 139,473 149,103 20,682 34,238 22,942 Tof 1.05 (1) in a number of Asian countries, notably India (2, n.a. Girl Boy Girl,Girl Mixed Boy,Boy 3), China (4, 5), and South Korea (6, 7). Availability of prenatal sex determination and induced abortion have been identified as Chinese, Koreans and Asian Indians important factors (3, 8), to the point of the former being 2.0 (ineffectively) banned in India and China.
    [Show full text]
  • Land Reform and Sex Selection in China⇤
    Land Reform and Sex Selection in China⇤ Douglas Almond, Columbia University & NBER Hongbin Li, Tsinghua University Shuang Zhang, University of Colorado Boulder December 1, 2013 Abstract Following the death of Mao in 1976, abandonment of collective farming lifted millions from poverty and heralded sweeping pro-market policies. Did China’s excess in male births respond to rural land reform? In newly-available data from over 1,000 counties, a second child following a daughter was 5.5 percent more likely to be a boy after land reform, doubling the prevailing rate of sex selection. We argue that having a son may be a normal good. Larger increases in sex ratios are found in families with more education and in counties with larger output gains from the reform. Proximately, sex selection was achieved in part through prenatal ultrasounds obtained in provincial capitals and increased mortality of female children. The One Child Policy was implemented over the same time period as land reform and is frequently blamed for increased sex ratios during the early 1980s. Our results point to China’s watershed economic liberalization as a more likely culprit. Keywords: Land Reform, Sex Selection, One Child Policy ⇤Sonia Bhalotra, Pascaline Dupas, Lena Edlund, Monica Das Gupta, Supreet Kaur, Christian Pop-Eleches, and Martin Ravallion provided helpful comments. We thank Matthew Turner for providing data on the 1980 rail network. Almond was supported by NSF CAREER award #0847329. 1 1Introduction Economic development has helped narrow key gender gaps over the past quarter century, including those in educational attainment, life expectancy, and labor force participation [World Development Report 2012].
    [Show full text]
  • Is Sex Ratio at Birth Changing in Italy? Spatial and Temporal Trends’ Analysis
    Is sex ratio at birth changing in Italy? Spatial and temporal trends’ analysis. Francesca Rinesi 1, Antonella Pinnelli 1, Sabrina Prati 2 and Francesco Lagona 3 1 “Sapienza”, Università di Roma; 2Italian National Institute of Statistics (Istat); 3Università di Roma Tre. Introduction and aim of the study In societies where no prenatal sex selection have been observed, male to female ratio at birth (secondary sex ratio) is commonly assumed to be relatively stable and it averages between 105 and 106 boys per 100 girls. Notwithstanding, some recent studies showed that in the last decades there has been a slightly but significant change in this ratio both considering Countries as whole and regions or small areas. According to Davis and colleagues (1998), a declining trend can be observed in Denmark, the Netherlands, Canada and US, whereas a comparative research carried out in 29 Countries reveals mixed results (Parazzini et al , 1998): between 1950 and 1994 the sex ratio shifted downwards in 16 countries, whereas it increased in 6 and remained roughly stable in the other 7. South Europe (including Italy) is one of the areas where the rise of sex ratio has been observed. Moreover, Astolfi and Zonta (1999) reported that during 1970-1997 the proportion of male births has significantly declined in the four most populated Italian provinces, while the opposite trend can be noted in the rest of the country. This means that aggregate national trend can obscured important variations in sex ratio across regions and, in general, across sub-national areas. The sex of newborns is dictated by biological and genetic factors.
    [Show full text]
  • Global Estimation and Scenario-Based Projections of Sex Ratio at Birth and Missing Female Births Using a Bayesian Hierarchical Time Series Mixture Model
    Global estimation and scenario-based projections of sex ratio at birth and missing female births using a Bayesian hierarchical time series mixture model Fengqing Chao*1, Patrick Gerland2, Alex R. Cook3, and Leontine Alkema4 1Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia 2Population Estimates and Projections Section, United Nations Population Division, Department of Economic and Social Affairs, United Nations, New York, NY, USA 3Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore 4Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA, USA December 1, 2020 Abstract The sex ratio at birth (SRB) is defined as the ratio of male to female live births. The SRB imbalance in parts of the world over the past several decades is a direct consequence of sex-selective abortion, driven by the co-existence of son preference, readily available technology of prenatal sex determination, and fertility decline. Estimation and projection of the degree of SRB imbalance is complicated because of variability in SRB reference levels and because of the uncertainty associated with SRB observations. We develop Bayesian hierarchical time series mixture models for SRB estimation and scenario-based projections for all countries from 1950 to 2100. We model the SRB regional and national reference levels, and the fluctuation around national reference levels. We identify countries at risk of SRB imbalances and model both (i) the absence or presence of sex ratio transitions in such countries and, if present, (ii) the transition process.
    [Show full text]
  • How Does the Two-Child Policy Affect the Sex Ratio at Birth in China? a Cross-Sectional Study S
    Fan et al. BMC Public Health (2020) 20:789 https://doi.org/10.1186/s12889-020-08799-y RESEARCH ARTICLE Open Access How does the two-child policy affect the sex ratio at birth in China? A cross-sectional study S. L. Fan1, C. N. Xiao2, Y. K. Zhang1,Y.L.Li1, X. L. Wang2 and L. Wang2* Abstract Background: The One-Child Policy led to the imbalance of the sex ratio at birth (SRB) in China. After that, Two- Child Policy was introduced and gradually liberalized at three stages. If both the husband and wife of one couple were the only child of their parents, they were allowed to have two children in policy (BTCP). If only one of them was the only child, they were allowed to have two children in policy (OTCP). The Universal Two-Child Policy (UTCP) allowed every couple to have two children. The objective of this study was to explore the changing trend of SRB at the stages of Two-Child Policy, to analyze the effect of population policy on SRB in terms of maternal age, delivery mode, parity, maternal education, delivery hospital, and to figure out what factors have greater impact on the SRB. Methods: The data of the study came from Hebei Province Maternal Near Miss Surveillance System, covered the parturients delivered at 28 gestation weeks or more in 22 hospitals from January 1, 2013 to December 31, 2017. We compared the SRB at different policy stages, analyzed the relationship between the SRB and population policy by logistic regression analysis. Results: Total 270,878 singleton deliveries were analyzed.
    [Show full text]